1. Field of the Invention
The present invention relates generally to a resealable closure mechanism such as may be used on a thermoplastic pouch.
2. Description of the Background of the Invention
Thermoplastic pouches having one or more resealable closure mechanisms extending along an opening into an interior thereof are often used to store perishable contents, such as food. In order to keep the food stored inside the pouch fresh for an extended period, a user may press excess air out of the pouch before completely sealing the closure mechanism. Other pouches have been developed that have a separate air evacuation route so that air may be removed from the pouch after the closure mechanism has already been sealed. Some such pouches allow a vacuum to be formed inside the pouch before the pouch is sealed so as to vacuum pack the contents of the pouch.
Special resealable closure mechanisms have been used in an attempt to maintain the vacuum in the pouch over extended periods of time. Those closure mechanisms have two opposing closure elements that form an interlocking section and a sealing section in an attempt to form an airtight seal. For example, in some such closure mechanisms, one closure element has a sealing member spaced between two in-turned hooks and the other closure element has a channel defined by and between two out-turned hooks. The sealing member abuts against inside surfaces of the out-turned hooks to form a seal therewith.
In other closure mechanisms, each closure element has a sealing member disposed between two interlocking members. The sealing members press against each other when the interlocking members are appropriately interlocked to form the seal. In one closure mechanism, for example, one closure element has two spaced out-turned male hooks that interlock with two complementary in-turned female hooks. A pressing rib spaced between the out-turned male hooks is wedged into a tapered channel defined by two tightening walls spaced between the in-turned female hooks. Each tightening wall also presses against an inner surface of the adjacent out-turned male hook.
In another closure mechanism, one closure element has two interlocking bulbous members spaced between two asymmetrical arrow-shaped members projecting from one base. The other closure element has three interlocking bulbous members spaced between two interlocking groove elements projecting from another base. The closure elements resealably mate with each asymmetrical arrow-shaped member interlocked with the opposing groove element and the two interlocking bulbous members on the one closure element engaged in a tight interfering fit between successive ones of the interlocking bulbous members on the other closure element. One of the closure elements has a backing member that may be attached directly to a pouch wall, and the other closure element has a backing member that is attached at only one end to another flange element that may be attached directly to a pouch wall.